Science of Sex: HIV and AIDS

Welcome to the seventh installment of a feature on Of Sex and Love that I call Science of Sex. In this feature, I discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

I update Science of Sex every second Saturday of the month — except for this one thanks to issues with connection, computers, and inspiration. Better late than never! 

Science of Sex HIV and AIDS

We’ll dive right in. I assume you all know that HIV, Human Immunodeficiency Virus, is a sexually transmitted infection that compromises the immune system by destroying CD4 T-cells. When it progresses to the most advanced stage, we refer to it as Acquired Immune Deficiency Syndrome or AIDS. In the final stage of HIV, the immune system has become too compromised to fight off HIV or other infections and illnesses (including pulmonary tuberculosis,  and recurrent pneumonia), which will take advantage of this time to infect the person. Treating the virus can put off progression to this final stage.

When HIV and AIDS first came on the scene in 1981, it was a death sentence. Within the first year, around half of the American men who were diagnosed with HIV died. There is much I could say about the cultural impact, especially because HIV/AIDS affected homosexual and bisexual (as well as their female partners), the most. We’re all familiar with the endemic and the ensuing panic that arose after the discovery of HIV.

While the infection remains an epidemic in some areas, including Cameroon and the Democratic Republic of Congo, where the infection originated, our understanding of HIV and AIDS has greatly increased over the last three and a half decades.

For example, promising tests of a new antibody in primates indicate that it is capable of preventing contraction of 99% of HIV strains. Testing on humans should begin next year. This is good news, but getting there was a difficult process for several reasons.

One of the main reasons that tackling HIV is difficult is becaise there are different types and subtypes of HIV. When most people speak of HIV, they mean HIV-1, which is the most common in the United States and the UK, among other locales. 95% of all HIV cases are HIV-1, but HIV-2 remains common in western Africa but has spread to other countries, and it’s even possible to contract a hybrid of the two strains.

Doctors have had the most success treating HIV-1, which is better understood. HIV-2 doesn’t respond to all of the treatments that HIV-1 responds to. It is less likely to develop into AIDS. People with HIV-2 are less likely to be diagnosed or to receive treatment for the virus, however. Originally, most HIV tests looked for HIV-1 antibodies, but modern tests search for signs of both types of HIV.

I’ll focus on HIV-1 from here because that’s what we know the most about and where we’ve made the most progress. HIV-1 presents challenges because there are 4 groups: M, N, O, and P. The majority of people in the M group have subtype B; although, subtypes A, C, D, F, G, H, J, and K exist as well as 89 hybrid viruses or ‘circulating recombinant forms’. Cameroon still has the widest variations of strains. Just like more research is needed into the other groups and the less common subtypes of group B, including CRFs,

There is good news when it comes to treatment, however. Because HIV is a retrovirus, researchers have designed antiretroviral therapies (ART), to treat people with HIV and also sexual assault victims who may have been exposed (official CDC guidelines recommend ART for high-risk victims). The first ART took six years to develop and approve, but there are now six categories:

  1. Entry Inhibitors work by stopping HIV entry into CD4+ cells
  2. Nucleoside Reverse Transcriptase Inhibitors, also known as nukes or NRTIs, help to block the reverse transcriptase proteins that HIV needs to multiply
  3. Non-Nucleoside Reverse Transcriptase Inhibitors, also known as non-nukes or NNRTIs, work by binding to and disabling the reverse transcriptase proteins that HIV needs to multiply
  4. Integrase Inhibitors block the enzyme that HIV needs to infect CD4+ cells with its genetic material
  5. Protease Inhibitors, also known as PIs, inhibit an enzyme that HIV needs to make copies of itself

When a doctor prescribes a combination of three ARTs from two different categories, it’s known as highly active antiretroviral therapy (HAART).

Between 2008 and 2014, new HIV infections dropped 18% in the United States with the biggest drops in drug users and heterosexuals. We lack research into HIV transmission rates for victims of sexual assault and sex workers. The data have is dated (around 1% of sexual assault survivors were tested for HIV in 1998, and half of them tested positive, presumably because they fell into the high-risk group. Furthermore, sex workers are ten times as likely to contract HIV, and approximately 12% of sex workers have the infection.), and change hasn’t been tracked. Hopefully, transmission rates have dropped for those groups as well.

The progress that has been made not only improves quality and length of life but reduces the risk of spreading HIV to new partners. The CDC has recently updated its HIV/AIDS guidelines for the first time since 1990. The updated guidelines finally indicate that the risk of spreading HIV-1 to sexual partners, to fetuses or infants via breastfeeding is virtually none as long as the person with HIV takes a daily HAART treatment. Mixed-status couples can safely try to conceive without worrying about the risk of HIV contraction.

While this has been one of the longer Science of Sex posts, it was one of the most fascinating to research. I knew very little about HIV/AIDS when I began, and encourage you to go through the extensive list of resources below if you want to know more about HIV.

Further Reading

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Dandi Lucas

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